A number of my indoor container plants have developed these shiny, white sunken spots, with tiny black spots nearby. They started on my oregano, on leaves at the base of the plant (not new leaves), and the black spots spread until entire leaves turned brown and died. It also affected my thyme, mint, sage, and here one of the most recent casualties, a chili pepper. The only nearby plant that it has skipped is rosemary.

Does anyone know what the cause may be? I’ve been removing affected leaves, but it’s still popping up. There isn‘t anything on the bottom of the leaves, but I have had aphid and spider mite issues.